Cast-in Shear Wall Anchor

ABSTRACT

A kit for enabling rapid and efficient installation of cast-in shear wall anchors is disclosed. The kit comprises a pre-manufactured base plate, a threaded rod segment of a predetermined length, a threaded coupler and a plug with a marker feature. The threaded rod segment is installed into the base plate and a threaded coupler is installed onto the threaded rod segment. The plug is installed into the threaded coupler. The plug features a marker feature that is preferably flexible, intended to protrude above the poured concrete surface to aid in locating the anchor after the concrete is cured, while the rest of the assembled anchor remains below the surface. The flexible nature of the marker feature prevents it from interfering with finishing equipment. The threaded rod segment is of a length predetermined to position the top of the threaded coupler just below the poured concrete surface in a typical installation. A range of on-site adjustment is possible by moving the threaded coupler up or down on the threaded rod segment.

The present invention relates to structural reinforcement in the construction of buildings and in particular to anchoring of shear walls to concrete foundations.

BACKGROUND OF THE INVENTION

In the construction of buildings it is common practice to structurally anchor walls to post-tensioned foundations and floors. One method of doing so is by means of tie downs. A tie down system typically consists of several threaded steel rods arranged vertically, with the lower end structurally anchored to the foundation and the upper end coupled to a structural member of a wall by means of a load bearing plate and a threaded nut. The threaded rods serve to prevent movement of the wall in adverse conditions such as high winds or earthquakes. As the wall begins to move in response to wind or earthquake loads, the threaded rods are placed in tension and exert a clamping force between the foundation and a wall structural member, preventing or limiting the movement. In addition to tie downs, the footer of the shear wall is commonly coupled to the concrete foundation by means of shear bolts or similar fasteners spaced at regular intervals.

In order to structurally couple threaded rods and other fasteners to the foundation, anchors are usually cast in place during the construction of the foundation. This is typically accomplished by placing a number of anchors into the form before concrete is poured. Most typical anchor bolts protrude above the level of the finished concrete by several inches in order to attach the sill plate after the concrete is cured. This is not desirable since the protruding anchor bolts interfere with, and can be damaged by, finishing equipment.

In common practice, an anchor is installed by tying “J” style anchor bolts to rebar placed in the form, and leaving the straight section of the bolt protruding up above the level of the finished surface of the concrete slab. Concrete is then poured into the form and covers the lower portion of the installed anchors. After finishing and cure, the form is removed and each anchor is left above the deck for attaching the sill plate. However the finishing is made difficult and time consuming by the protruding portion of the anchors.

In a previous improvement by the authors of the present invention, a submerged anchor is created by first attaching a base plate to the bottom of the concrete form, usually by means of common nails or screws. Such a base plate may consist of a rectangular or round metal plate with a threaded nut welded to it. A plurality of such plates are placed into the form at predetermined intervals. Segments of threaded rod are then cut to an appropriate length and threaded into the base plates. A threaded coupler is then installed on each threaded rod segment, positioned at such a height that its top is just below the finished surface of the concrete. A plug is then installed in each threaded coupler to prevent entry of concrete inside the coupler during the pour which covers the-installed anchors. After finishing and cure, the form is removed and the location of each anchor is determined by measurement or other means such as detection equipment. Concrete is then chipped away to uncover the top of the anchor and the previously installed plug is removed so that threaded rod or other fastener may be installed into the now exposed threaded coupler.

With hundreds of anchors needed in a typical installation, the commonly practiced methods are labor intensive and inefficient. The previous improvement by the authors greatly simplifies the finishing of the poured concrete but still requires additional labor to install and subsequently locate and expose the submerged anchors. What is needed is a pre-assembled anchor system, supplied as a kit, which enables quick and efficient installation of the anchors into the concrete form as well as efficient location and access of the installed anchors after the concrete is cured, without interfering with finishing equipment. The Shear Wall Anchor of the present invention answers this need.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide a complete and ready kit for the rapid and efficient installation of cast-in Shear Wall Anchors. The kit comprises a pre-manufactured base plate, a threaded rod segment of a predetermined length, a threaded coupler and a plug with a flexible marker feature. The threaded rod segment is installed into the base plate and a threaded coupler is installed onto the threaded rod segment. The plug is installed into the threaded coupler and prevents entry of concrete into the coupler during the pour. The plug features a flexible marker feature, intended to protrude above the poured concrete surface to aid in locating the anchor after the concrete is cured, while the rest of the assembled anchor remains below the surface. The flexible nature of the marker feature prevents it from interfering with finishing equipment. The threaded rod segment is of a length predetermined to position the top of the threaded coupler just below the poured concrete surface in a typical installation. A range of on-site adjustment is possible by moving the threaded coupler up or down on the threaded rod segment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described herein with reference to the following drawings:

FIG. 1 shows the components of the Shear Wall Anchor of the present invention;

FIG. 2 is a further illustration of a base flange;

FIG. 3 illustrates the typical installation of the Shear Wall Anchor prior to pouring of concrete; and

FIG. 4 shows the cross-section view of a typical installation after concrete is poured.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

An embodiment of the present invention is shown in FIG. 1. In order to facilitate rapid and efficient installation of Shear Wall Anchors into a form, the kit of the present invention comprises a base flange 100, a threaded rod segment 200 which has been cut to a predetermined length, a threaded coupler 300 and a plug 400.

The base flange 100, further illustrated in FIG. 2, serves to secure the Shear Wall Anchor assembly to a form prior to pouring concrete. In the embodiment disclosed herein, the base flange 100 is formed from plastic or similar material by injection-molding the flange 120 with a steel flanged nut 110 molded in as an insert. Molded-in inserts are well known in the art and this commonly practiced process need not be discussed in detail herein. The complete base flange 100 is preferably secured to the form by means of nails, screws or other commonly available means. It is to be noted that the purpose of the base flange is only to position and secure the Shear Wall Anchor assembly in the form prior to and while the concrete is poured and cured. In the disclosed embodiment, the flanged nut 110 serves as the means to structurally retain the threaded rod segment 200. The pull-out strength of the installed Shear Wall Anchor is provided solely by the load-bearing face 150 of the nut 110 bearing against the cured concrete. The flange portion 120 of the base flange 100 plays no structural role once concrete is cured.

In addition to the injection molding method disclosed herein, many other methods of constructing the base flange 100 shall be apparent to those skilled in the art, including welding or bonding of the nut 110 or similar threaded fastener to a flange 120 made of either metallic or non-metallic material. Embodiments wherein the base flange 100 is a monolithic part are possible without departing from the scope of the present invention, as long as the flange is configured to receive and structurally retain a threaded rod segment 200, provides a load bearing face 150 and is sized sufficiently to provide stability to the Shear Wall Anchor assembly prior to and while the concrete is being poured. One example of such a base flange may be a monolithic cast iron unit which is shaped and sized similar to the base flange illustrated in FIG. 2. Many examples of such castings exist in the art.

FIG. 3 illustrates a complete Shear Wall Anchor assembly, supplied as a kit, installed in a form prior to pouring concrete. The base flange 100 is secured to the floor of the form by means of nails, screws, or other similar means. The threaded rod segment 200 is supplied in the kit of the present invention pre-cut to a predetermined length so as to create an assembly with overall installed height substantially equal to the depth of commonly used concrete forms. The threaded coupler 300 provides a range of adjustment in the field, if such is found necessary, by threading up or down on the threaded rod segment.

The plug 400 features a flexible marker feature 410. It serves two functions within the kit of the present invention. First, it prevents the entry of uncured concrete into the threaded coupler while the concrete is poured and subsequently compacted. A completed installation is further illustrated as a cross-sectional view in FIG. 4. The second function of the plug 400 is to aid in locating and uncovering the Shear Wall Anchor after the concrete is cured. The flexible marker feature 410 by protrudes above the cured surface 610 of poured concrete 600 to aid in locating the anchor. Its flexibility prevents it from interfering with finishing equipment that is commonly used to ensure the concrete is fully settled during cure. The marker feature 410 preferably consists of one or more plastic whiskers and is similar in nature to bristles on a brush. The marker feature may be molded integral to the plug or installed as a secondary operation. The forming of flexible bristles is well known in constructions of brushes of various types and therefore the details of the process need not be discussed herein.

After concrete 600 is cured, the installed Shear Wall Anchor is located with the aid of flexible marker feature 410 and the plug is removed exposing the threaded portion of the threaded coupler 300. A thin layer of concrete may be chipped away or otherwise removed in the process, as is commonly practiced in the art.

By supplying a complete, pre-configured assembly of the Shear Wall Anchor as a kit the present invention facilitates substantial savings in labor, cost and construction time as compared to currently known and practiced methods.

The embodiment disclosed herein is illustrative and not limiting; other embodiments shall be readily apparent to those skilled in the art based upon the disclosures made herein, without departing from the scope of the present invention. 

1. A Shear Wall Anchor kit, comprising: a base plate having a means of structurally retaining a threaded rod and further having a means of being attached to the floor of a concrete form; a threaded rod segment of a predetermined length; a threaded coupler; and a plug configured to be installed in said threaded coupler.
 2. The Shear Wall Anchor kit of claim 1 wherein said plug comprises a marker feature.
 3. The Shear Wall Anchor kit of claim 1 wherein said means of structurally retaining a threaded rod is a flange nut.
 4. The Shear Wall Anchor kit of claim 3 wherein said base plate is formed from plastic by means of injection molding.
 5. The Shear Wall Anchor kit of claim 2 wherein said marker feature is at least a plastic whisker.
 6. The Shear Wall Anchor kit of claim 2 wherein said marker feature is a plurality of plastic whiskers.
 7. A method of installing a Shear Wall Anchor comprising the steps of: (a) positioning a threaded coupler in the concrete form entirely below the level of the finished concrete surface by means of a support, (b) installing a plug in said threaded coupler, said plug having a marker feature, said marker feature being positioned at least in part above the level of the finished concrete surface, (c) pouring, curing and finishing the concrete and subsequently removing the form, (d) locating the anchor by means of said marker feature and exposing said threaded coupler for access by removing said plug.
 8. The method of claim 7 wherein said support is a threaded rod section of a predetermined length, coupled to a base plate.
 9. The method of claim 7 wherein said support, said threaded coupler and said plug are supplied as a kit. 